The present invention relates to a hydraulic damper of the type having a piston rod, and more particularly a rod guide for a piston rod in a hydraulic damper.
Japanese Patent Second (examined) Publication Tokko-Sho 62-38574 discloses a hydraulic damper. This known hydraulic damper comprises an outer shell, a cylinder disposed in the outer shell, and a piston rod disposed in the cylinder. A cap covers an open axial end of the outer shell. The piston rod has a piston slidably disposed in the cylinder, and extends through the cap. The piston divides the cylinder into an upper chamber adjacent an axial open end of the cylinder and a lower chamber adjacent the closed axial end of the cylinder. The cylinder and outer shell cooperate with each other to define therebetween a reservoir chamber. In order to guide the piston rod, this hydraulic damper comprises a bearing formed by pressing a sheet of a low friction material, and an insert of a metal. The bearing has an outer sleeve portion coupled with the cap which is in turn coupled with the outer shell and an inner sleeve portion with an inner peripheral wall held in slidable engagement with the piston rod. The insert is fixedly connected to the bearing and coupled with the cylinder. In order to prevent oil leakage past between the cap and the piston rod, a sealing assembly is provided. This sealing assembly includes a packing and a packing spring. The packing spring having one end bearing against a radially extending portion of the bearing and an opposite end bearing against a packing back-up plate.
An object of the present invention is to improve a hydraulic damper of the above-mentioned type in such a manner as to guide a piston rod without using a bearing formed by pressing a low friction material which is expensive.